ZAGREB (Reuters) - Croatia has asked Austria and Germany to explain why they did not act on an international arrest warrant and detain the head of Hungarian energy firm MOL when he was on their territory, the interior minister said on Thursday.

MOL's chairman, Zsolt Hernadi, is charged in Croatia with giving former prime minister Ivo Sanader a 10 million euros ($ 11.40 million) bribe to secure a dominant position for MOL in Croatia's energy group INA.

Croatian state news agency Hina, citing MOL's spokesperson, reported that Hernadi was on a business trip in Vienna this week and that he had visited Germany several times this year.

"We filed a note asking how this was possible. It is obligatory to act on an arrest warrant," Interior Minister Ranko Ostojic told Hina in Opatovac in eastern Croatia.

MOL, Sanader and Hernadi all deny wrongdoing.

Hernadi is accused of bribing Sanader in late 2008 for MOL to secure dominant management rights in INA where it has close to 50 percent with the Croatian government holding a bit less than 45 percent.

Croatia said Hernadi would be tried in absentia, but the trial has not started yet.

Croatia's Constitutional Court annulled a jail sentence for corruption against Sanader in July and ordered a retrial, saying he had not been fairly treated at the original hearing.